Exam 1 Flashcards
Pharmacodynamics?
What the drug does to the body
Pharmacokinetics?
What the body does to the drug
Agonist?
Binds to receptor and elicits an effect downstream
Antagonist?
Binds to receptors & inhibits effect of agonist
(does not increase or decrease agonist)
Endogenous agonist?
Naturally product in the body.
Ex: Dopamine
Orphan receptor?
Endogenous ligand. Don’t know what it binds to or does.
Poisons?
From Non-living Ex: Arsenic, lead
Toxins?
From Living organisms Ex: pufferfish, Botox
Problem with drugs >1,000MW?
Difficulty crossing barrier & excreting
What must drugs have to bind to receptor?
Right size, charge, shape, atomic composition
Strongest bond?
Covalent bond, usually irreversible
Orthosteric receptors?
Active site, where native ligand binds
Allosteric receptor?
Binding elsewhere on the receptor(protein), are non-competitive, can change the shape of different receptor site. Activating or inactivating it.
What is Ec50?
50% effect of the drug
What is Kd?
50% of receptors are bound by the drug.
What does Low Kd mean?
High receptor affinity. Ex: Covalent bond= low Kd
What do an agonist & allosteric activator create & Example?
A synergystic effect- max effectiveness w/ less drug. Ex: Morphine & phenergan
What if an agonist & competitive inhibitor mix?
More agonist needed to produce effect.
What is an agonist mimic?
Indirect agonist- doesn’t act at receptor & prolongs effect.
Blocks enzyme that breaks down downstream effect.
Example of Charge Antagonism?
Protamine (+) binds to and inhibits Heparin (-).
Physiologic antagonism?
Drugs act at different receptors to squelch effect of other drugs. Cause opposite effect.
Ex: one drug increase HR & one drug decrease HR.
Proteins favor what kind of receptor?
Inactive form
Drugs favor what kind of receptor?
Active receptors
what does an Inverse agonist do?
Higher affinity to the inactive form, acts as an antagonist to keep receptor inactive and/or
causes opposite effects produced by conventional agonist at the receptor.
What is Potency?
Concentration of drug (ED50) needed for 50% of the drug’s effect.
What is Max efficacy?
Greatest possible response a drug can deliver
Depends on interaction with receptor
Clinical effectiveness?
Max effect, not max potency
What does ED50 mean?
Effective dose=50% of population have the benefit from the drug.
What is TD50?
Toxic dose=50% of population have toxic effect.
What is Therapeutic Index and how is it calculated?
TD/ED= calculates the safety of the drug
What is tachyphylaxis?
Quick tolerance
What are exogenous receptors?
Receptor activated by external compounds
Describe the relative bond strengths
1: Covalent bond= strongest bond
2: Electrostatic (charged molecules, H+ bonds, Van Der Waals forces)
3: Hydrophobic- Lipid soluble forces
Discuss the four main causes of drug variation.
1: Alteration in concentration that reaches receptors
- Age, weight, sex, disease state, rate of absorption, clearance
2: Variation in concentration of endogenous receptor ligand
3: Alteration in number or function of receptors
4: Changes in components of response distal to receptor
- Post receptor process, body compensation, largest & most important cause
What is Toxicology?
- Study of toxins & poisons
- Undesirable effect of chemicals on living systems
Pharmacogenomics?
How genetic makeup affects the drug response
Distinguish between a competitive inhibitor and an allosteric inhibitor.
1: Competitive inhibitor: molecule that binds to active receptor site
2: allosteric inhibitor: Binds to enzyme/receptor surface changing active receptor site.
Describe physiologic antagonism.
Behavior of a substance that produces effects counteracting those of another substance using a mechanism that does not involve binding to the same receptor.
Describe the role of drug carriers, and list the most common ones in the blood.
Albumin: Binds most acidic drugs
Alpha1-acid glycoprotein: binds most basic drugs
Lipoproteins binds most neutral drugs
Describe the following term: partial agonist
Partial agonist: bind-to and activate a given receptor, but have only partial efficacy at the receptor.
Describe inverse agonist.
Ligand that binds to the same receptor-binding site as an agonist and not only antagonizes the effects of an agonist but, moreover, exerts the opposite effect by suppressing spontaneous receptor signaling
Define racemic mixtures, and correlate stereoisomerism and differences in drug effects.
Example?
A 50/50 mixture of two enantiomers(mirror image of a drug).
Example: Ketamine (S)= 4x more potent & (R)= more toxic.
Explain all 4
A= Agonist alone
A+C= Synergistic effect- max effect with less drug
A+B= More agonist needed to outcompete B to produce same effect
A+D= insurmountable, non-competitive= allosteric inhibitor
What are ligands?
Molecules that bind to receptor sites.
Define receptor
a cell or group of cells that receives stimuli. : a chemical group or molecule (such as a protein) on the cell surface or in the cell interior that has an affinity for a specific chemical group, molecule, or virus
Compare the efficacy and the potency of 2 drugs on the basis of their graded dose-response curves.
- B is the most potent drug.
- A, C, D have equal efficacy but A is more potent out of A, C, D
Describe “trapping” of a drug.
Alter the pH of urine to change the charge to trap it in the urine.
- Acidic drugs are excreted faster in alkaline urine.
- Basic drugs are excreted faster in acidic urine.
Evaluate how a partial agonist can also be an antagonist.
A partial agonist blocks the full agonist’s receptors and only exerts a fraction of the desired effect.